JPH0362750A - Method of communication between vehicles on road - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial application field> The present invention relates to a road-to-vehicle communication method, and more specifically, the present invention relates to a road-to-vehicle communication method, and more specifically, it communicates with a receiving device mounted on a vehicle, and transmits information to the vehicle about its current position, direction of travel, and traffic information. This invention relates to a road-to-vehicle communication method for providing information.

<Prior art> The roadside beacon method is the predecessor of the roadside vehicle-to-vehicle communication method, and the roadside beacon method radiates beacon radio waves carrying the position data of the roadside antenna into a narrow area, thereby limiting the radiation area of the roadside antenna. Its purpose was to provide passing vehicles with data for calibrating the position and orientation of their navigation systems.

However, road-to-vehicle communication methods are being considered that provide not only the above-mentioned location data but also the following traffic information as an additional service to alleviate the recent road abrasions. In other words, 1) By providing the navigation system with additional traffic information such as road congestion, construction, and other road usage conditions around the location where the roadside antenna is installed, it assists the smooth operation of vehicles. 2) Adding detailed map information including residential locations and personal names around the location where the roadside antenna is installed to make it easier to reach the final destination; 3) Where the roadside antenna is installed By adding road map information covering a fairly wide range, including the locations where the vehicle is located, and providing it to the navigation system, the road map displayed on the display device can be updated to ensure smooth operation to remote locations. 4) In addition to providing the above-mentioned map data, etc., by providing a heading indicator, the orientation sensor of the in-vehicle device (navigation device) can be omitted, thereby reducing the cost of the in-vehicle device (navigation device). The objective is to expand the use of road-to-vehicle communication methods.

By the way, if such a large amount of data is to be provided as an additional service, it is necessary to expand the transmission band radiated from the roadside antenna and the area covered by the transmitted signal.

As described above, when the transmission area is expanded and the area covered by the transmitted signal is expanded, the reception area expands and the detection of the direct position of the roadside antenna increases, which is the original purpose. A problem arises in that the vehicle position cannot be calibrated accurately due to the influence of the two notes.

In order to solve the above problem, the inventors of the present invention have already proposed a road-to-vehicle communication method in Japanese Patent Application No. Sho [i3-45BJB].

The road-to-vehicle communication method according to the earlier application is that ``a roadside antenna is configured with two antenna elements whose main radiation direction is %, and modulated with mutually different data corresponding to position data and road direction (PSK, FSX, or ASK). modulation)
The modulated wave signal is divided into two, amplitude modulation is performed on the two divided signals with opposite phases to each other to generate a second modulated wave signal, and this second modulated wave signal is made to be in phase with the first modulated component. As shown in FIG. 6 of the present application, the first modulated wave signal component has a wide transmission range, and the second modulated wave signal component has a field strength that drops sharply at the position directly opposite the roadside antenna. and appear at the same time.

Then, on the vehicle side, the first modulation component is extracted and various data are restored, the amplitude modulation component is extracted, a sharp drop point of the amplitude modulation component is detected, and this drop point is position. In addition, the phase of the second modulated wave signal is synchronously detected, and it is determined which main radiation region of the roadside antenna it is located in based on whether the phase changes from normal phase to negative phase or from negative phase to positive phase. to identify the direction of travel. ”
This is the content. That is, the in-vehicle device, for example,
This is a configuration that combines a data demodulator configured with SK, FSK, or ASK demodulation method and an AM demodulator.

<Problem to be Solved by the Invention> By the way, in the above-mentioned prior invention, the vehicle side receiving device is equipped with a receiver compatible with the modulation method of the roadside device. However, in order to provide a large amount of information, the roadside equipment side modulation method and PSK or FS, which have high performance in 1-7, are used.
If K is adopted, a receiver using the A or SK demodulation system will not be able to obtain position data or heading data. This would result in the provision of additional services resulting in higher costs for PSK or FS.
This would force a K-scheme receiver, making it impossible to achieve simplicity and cost reduction. Therefore, there is a problem that the road-to-vehicle communication method becomes far removed from the original purpose of providing position data and direction data to as many vehicles as possible.

The present invention was made in view of the above-mentioned problems.
Roadside beacons that enable the modulation of roadside equipment to transmit large amounts of traffic information and also provide location data and road direction data to vehicles equipped with ASK demodulation receivers. The purpose is to provide.

Means for Resolving the Problems> In order to achieve the above-mentioned object 1, the present invention divides a first modulated wave signal subjected to PSK, FSK or ASK modulation based on a transmission data frame into two parts, and divides the first modulated wave signal into two parts. ASK modulation is carried out based on data including at least different direction identifications to generate a composite wave signal by the first modulated wave signal and SK modulation, and the composite wave signal has different main emission directions. The present invention is characterized in that a signal transmitted from the roadside antenna is radiated from the roadside antenna, a receiving device mounted on the vehicle receives the transmission signal from the roadside antenna, performs at least ASK demodulation, and obtains direction identification data from the demodulated signal.

The roadside device also includes a data modulation unit that performs PSK, FSK, or ASK modulation on the transmission data frame, a clock signal that is synchronized with at least the transmission data frame, and a different It consists of two ASK modulation means that perform amplitude modulation based on a data frame containing direction identification data, and at least one pair of antenna elements having mutually different main radiation directions and each fed with a signal modulated by the two ASK modulation means. The present invention is characterized in that it has a roadside antenna.

Effects> According to the present invention, the roadside antenna of the roadside device receives, in addition to the first modulated wave signal subjected to PSK, FSK, or ASK modulation based on the transmission data frame, a signal that includes at least direction identification. A second modulated wave signal (ASK modulated signal) with amplitude modulation based on the pig is transmitted to each main radiation region.

A receiving device mounted on a vehicle receives a transmission signal from a roadside antenna and reproduces an ASK modulated signal.

Then, data identifying the main radiation direction of this ASK modulated signal is extracted.

Next, based on the extracted direction identification data, it is detected which main radiation direction area of the roadside antenna the vehicle is in.

Furthermore, the position of the roadside antenna is detected based on the tabulation of the direction identification data when the vehicle moves and enters the radiation area without force from one main radiation area, and the position of the roadside antenna is detected. Set the detection point as the current position.

Therefore, if the in-vehicle device is equipped with an ASK demodulation type receiving device, it is possible to detect at least the traveling direction and the current position.

Furthermore, if a receiving device is provided that combines the conventional PSK, FSK, or ASK modulation method with the above-mentioned ASK demodulation method, it will demodulate the transmitted data frame based on the first modulated wave signal as well as the first modulated wave signal. It is possible to demodulate the amplitude modulation component by perturbing the modulated wave signal of No. 2, and all the pigs provided from the roadside device can be taken in based on these demodulated signals.

<Embodiment> An embodiment of the present invention will be described below in detail 1 with reference to the drawings.

FIG. 3 shows an example of a split beam antenna installed on the roadside, and the split beam antenna 1 is installed in the A direction (
The configuration includes an antenna element 2 having a main group JIJ direction (for example, an upstream direction) and an antenna element 1 having a main radiation direction of a B direction (for example, a downstream direction). As shown in FIG. 4, this antenna 1 exhibits directivity in which the radiated electric field strength slightly decreases at the boundary line of the main radiation direction.

FIG. 1A is a configuration block diagram of a roadside device according to an embodiment of the present invention, and FIG. 2 is a waveform diagram schematically representing the signals in FIG. 1A.

The data transmitter H is a component that converts road information, traffic information (in the case of a two-way communication roadside beacon system, includes data such as messages from vehicles and FAX data) into a serial code string and outputs the same.

The signal sent from the data transmitter t1 is intermittently and repeatedly sent out in frame units, as shown in "A: Transmission data frame" in FIG. traffic information in direction B and traffic information in direction B.

Here, the header arranged at the beginning of the frame is a part having functions necessary for communication such as code element synchronization and frame synchronization. Further, the transmission rate of the transmission data frame is set to 512 kbps in this embodiment]1.

The transmission data frame sent from the data transmitter 1 is
A data modulator 12 is provided.

The data modulator 12 modulates the carrier wave fc (carrier wave whose center frequency is fc) provided from the carrier wave generator i4 with a transmission data frame to generate a first modulated wave signal. As a modulation method in the data modulator 12, a PSK modulator, an FSK modulator, or an ASK modulator is used.

The first modulated wave signals produced by data modulator 12 are supplied to amplitude modulators 15 and 16, respectively.

The modulation signal generator 13 generates two types of data S1. for the A direction and for the B direction. S2 is generated, and this transmission data Sl, S2
This is a component that converts the code into a serial code and outputs it. The data sent from the modulation signal generator] 3 is as shown in "B, Transmission data frame" in FIG.
They are derived from the synchronization clock, A direction identification data, and position data, respectively. In addition, as shown in the "C sending f... data frame", it is composed of a synchronization clock, B direction identification data, and position data.

The second synchronization clock counts down the same clock signal used by the data transmitter 11, and is set to a frequency that is 1/32 of the synchronization signal of the data transmitter 11. The frequency of the clock signal is set at a ratio that allows separation of the transmission data from the receiving side or the data transmitter 11 and the transmission data from the modulation signal generator 13, and this ratio is 1/8 or more. If so, it is separable. The above-mentioned direction identification data corresponds to the radiation area of the split beam antenna 1, and in this embodiment, it is distinguished by "0" and "1" depending on the radiation area. The above location data is
These are the coordinate positions of the split beam antenna 1. In addition,
It is possible to include road orientation data (3 to 4 bits) obtained by dividing 360° into 8 to 16 equal parts in the position pigeon in the transmission data.

The signal S1 output from the modulation signal generator 13 is supplied to the amplitude modulator 15, and the signal S2 is supplied to the amplitude modulator 1.
6.

Amplitude i, 7. The J unit 15 amplitude-modulates the first modulated wave signal supplied from the data modulator 12 with the modulated signal S1 of the modulated signal generator 13, and the modulation rate of the modulated signal S1 is as follows.
It is selected to be 0.5 or less. A first modulated wave signal that is amplitude modulated or FSK modulated is generated, and this first modulated wave signal is converted into an ASK modulated wave signal that is amplitude modulated using a synchronization clock, direction identification data, and position data. By radiating this, direction identification data and position data can be provided even if the in-vehicle device is an ASK demodulation receiving device. In addition, there are receiving devices that combine the conventional PSK demodulation method and AM demodulation method, and receivers that combine the conventional PSK demodulation method and AM demodulation method.
A receiving device that combines demodulation methods, or a receiver that combines ASK demodulation method and AM demodulation method, etc. (for example,
In addition to direction identification data and position data, a large amount of traffic information can be provided to the vehicle-mounted device shown in the road-to-vehicle communication method of Japanese Patent Application No. 83-45616.

FIG. 1B is a block diagram showing an example of an in-vehicle receiver using the ASK demodulation method.

In FIG. 18, a signal radiated from a split beam antenna 1 of a roadside device is received by a receiving antenna 21, this received signal is amplified to a required level by a receiving amplifier 22, and is supplied to an ASK demodulator 23. . The ASK demodulator 23 is connected to the amplitude modulator 15, 16 (FIG. 1A) of the roadside device.
), which demodulates the modulated signals SL and S2 and supplies them to the data processing section 24.

The data processing unit 24 extracts direction identification data and position data from the demodulated signal supplied from the ASK demodulator 23,
Direction identification data is "0°゛-"1' or "1" → "0"
This component performs processing such as detecting the facing position of the split beam antenna 1 based on the inversion. Specifically, the data processing section 24 is configured by a microcomputer or the like. The output of the data processing section 24 is displayed on the display section 25 so that it can be visually recognized by the driver of the vehicle or the like. Note that it is also possible to mount a navigation device in place of the display section 25.

FIG. 5 is a diagram for explaining the receiving operation of the receiving device shown in FIG. 1B while the vehicle is running.

5 In FIG. 5(a), AB corresponds to the direction AB in FIG. 3, and represents the direction of the road.

A second modulated wave signal is radiated onto this road from the split beam antenna 1 of the roadside device with split beam characteristics of a main radiation beam in the A direction and a main radiation beam in the B direction.

Suppose a vehicle is traveling along the road towards A-B.
A receiving device mounted on the vehicle enters the beam emission area of square A and receives the radiated radio waves. The signal received at this time and output from the reception amplifier 22 is supplied to the ASK demodulator 23. The ASK demodulator 23 demodulates the modulated signal S1 and supplies it to the data processing section 24. Then, the data processing section 24 determines that the direction identification data of the modulated signal S1 is "0", and the position data is stored in the memory within the data processing section 24.

Next, when the vehicle continues to drive and approaches the split beam antenna, the data in the forward direction and the data in the B direction will interfere with each other, making it impossible to identify the direction.

] 6 Furthermore, when the vehicle continues to drive and passes the position directly facing the Svri Sotvim antenna 1 and enters the main radiation area in the B direction, 1. In the same manner as when the vehicle is traveling in the direction of AB described above, data in the B direction is received and supplied from the reception j width filter 22 to the ASK demodulator 23. The modulated signal S2 demodulated by the ASK demodulator 23 is supplied to the data processing unit 24, and the data processing unit 24 determines that the direction identification data of the modulated signal SS2 is “1”. That is, it is detected whether the object has moved from direction A to direction B. When this direction identification data is reversed, the position data stored in the memory is supplied to the display section 25, and this is displayed as the current position.

Furthermore, if a navigation device is installed instead of the display unit 25, position calibration and orientation calibration are performed based on position data. Furthermore, if the modulated signal SIS2 includes road orientation data, it is possible to display the traveling orientation on the display unit 25 or to use it as orientation calibration data for a navigation device.

] 7 However, if the vehicle is traveling from B to A on the road,
The operation of the receiving device is opposite to that described above, and first, the modulated signal S2 in the B direction is received.

In the case of the above-mentioned in-vehicle device using the ASK demodulation method, the ASK demodulator 23 uses the modulated signal Sl transmitted from the roadside device.
, S2 and the data processing unit 24 extracts direction identification data, position data, etc., so that the driver can recognize the current position and the direction of travel. Therefore, even with the low-cost ASK demodulation method, the current position and the direction of travel can be detected, making it possible to increase the number of vehicles that utilize the road/vehicle+q1 communication method.

<Effects of the Invention> As described above, in the present invention, a roadside antenna is configured with two antenna elements having different main radiation directions, and various data l components other than data identifying the main radiation direction and position data are transmitted. Direction identification data is carried by ASK modulation with a data frame containing at least direction identification data in a signal carried by a first modulation method such as PSK, FSK or ASK modulation, and power is supplied to each antenna element. By doing so, even if the receiving device on the vehicle side uses the ASK demodulation method, it is possible to extract the amplitude modulation component and perform position detection and direction detection. In addition, conventional high-performance receiving devices (for example, Japanese Patent Application No. 63-4561
For the invention of No. 6, combination of PSK demodulation method and AM demodulation method, combination of FSX demodulation method and AM demodulation method, etc.), the amplitude modulation component is extracted as before. In addition to performing position detection and direction detection, it is also possible to extract the first modulation component and restore various data.

[Brief explanation of drawings]

FIG. 1A is a configuration block diagram of a roadside device according to an embodiment of the present invention, FIG. 1B is a configuration block diagram of a receiving device mounted on a vehicle according to an embodiment of the present invention, and FIG. A diagram for explaining signals of each part of the roadside device shown in FIG. 1A; FIG. 3 is a schematic perspective view showing a configuration example of a lit beam antenna; 4
Figure 5 is a diagram showing the electric field strength distribution of radiated radio waves in a split beam antenna, Figure 5 is a diagram for explaining the operation of the receiving device shown in Figure 1B, Figure 6 is a diagram showing the powder of the roadside device of the earlier application. FIG. 3 is a diagram showing electric field strength. 1... split beam antenna,

Claims (1)

[Claims] 1. In a road-to-vehicle communication method for transmitting and receiving various data between a roadside device installed on the roadside and a vehicle, PSK, FSK, or ASK modulation is performed based on a transmitted data frame. dividing the first modulated wave signal into two and performing ASK modulation on each of them based on data including at least different direction identifications to generate a composite wave signal by the first modulated wave signal and SK modulation;
This composite wave signal is radiated from roadside antennas having different main radiation directions, and a receiver mounted on the vehicle receives the transmitted signal from the roadside antenna, performs at least ASK demodulation, and uses the demodulated signal to determine the direction of radiation. A road-to-vehicle communication method characterized by acquiring identification data. 2. The roadside device according to claim 1 above includes data modulation means for performing PSK, FSK, or ASK modulation based on a transmission data frame, and a clock that is synchronized with at least the transmission data frame, respectively, for the PSK, FSK, or ASK modulated signal. two ASK modulation means for amplitude modulating a signal and a data frame comprising different direction identification data; and at least one pair of antennas having mutually different main radiation directions and fed with signals modulated by the two ASK modulation means. A roadside antenna consisting of an element.